The answer is 33. This is because there are 3 colours and the probability that the spinner will land on each colour is 1/3 (one third). To work out the number of times it will land on blue you have to do the probability of it landing on blue (1/3) multiplied by the number of times spun (100) which gives approximately 33.
Eight and six tenths in decimal form is 8.6
After staring at this for a few seconds, I think the equation
![-5\sqrt{10}\cdot\sqrt{15}=[1]\sqrt{[2]}](https://tex.z-dn.net/?f=-5%5Csqrt%7B10%7D%5Ccdot%5Csqrt%7B15%7D%3D%5B1%5D%5Csqrt%7B%5B2%5D%7D)
is asking you to simplify the left hand side so that it has a form matching the right hand side, and [1] and [2] are placeholders. My guess is that they're supposed to be integers.
Notice that



Then multiplying by -5, we have

so I believe [1] = -25, and [2] = 6.
1 pack has 5 seperate packs, each with 10 pieces
=>50 pieces
50*3=150 pieces of gum
This is true. You can remember by it saying mid, as in middle.